Going Cellular With Your Arduino Projects

February 5, 2011 by Mike Szczys 44 Comments

You can add a huge measure of extensibiltiy to a project by using a cellular connection. Anywhere the device can get service you can interact with it. In the past this has been a pretty deep slog through datasheets to get everything working, but this tutorial will show the basics of interacting with phone calls and text messages. It’s the 26th installment of what is becoming and mammoth Arduino series, and the first one in a set that works with the SM5100B cellular shield.

We love the words of warning at the top of the article which mention that a bit of bad code in your sketch could end up sending out a barrage of text messages, potentially costing you a bundle. But there’s plenty of details and if you follow along each step of the way we think you’ll come out fairly confident that you know what you’re doing. Just promise us that you won’t go out and steal SIM cards to use with your next project. Find part two of the tutorial here and keep your eyes open for future installments.

Cheap And Easy SMS Via GSM For Your MCU

October 18, 2010 by Jakob Griffith 68 Comments

Non acronym version of the title: send and receive text messages via cell phone communication towers using an Arduino or other microcontroller. “We’ve been doing that for years!” you cry, well yes, technically. But [Fincham] lays it outs simply; commercial offerings are expensive and finding a cell phone that uses RS232 now a days is getting difficult, so a new way of doing the same old is necessary. The good news is USB GSM modems are readily available, cheap, and only require a few interface pins to get them talking with an Arduino. In fact, the image above is all you need.

Modem Used In An Alarm System

August 25, 2010 by Mike Szczys 22 Comments

This alarm system senses motion and then alerts you by phone. [Oscar] had an old external modem sitting around and, with some wise hardware choices, he came up with a simple circuit to use it. First up is the PIC 16F628A chosen because it doesn’t require an external crystal. This connects with the modem via a DS275 RS232 transceiver because it requires no external parts for connection. The final portion of the puzzle is a PIR sensor that triggers a pin interrupt in the sleeping PIC, which then dials your number to alert you. It doesn’t look like anything happens other than your phone ringing, but that’s enough for a simple system. We’re just happy to see how easy it was to use that modem… time to go hunting for one in dreaded junk trunk. Don’t miss the clip after the break.

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Texting With Some Walkie-talkies

July 7, 2010 by Mike Szczys 44 Comments

[Travers Buda] is giving new life to his abandoned childhood toys. He cracked open a set of Family Radio Services radios he had received for a birthday which work up to 2 kilometers apart. With just a bit of extra circuitry he was able to get them to act as wireless modems. The system functions but it looks like it would benefit from some more refinement, including error correction. In the end [Travers] manages to send and receive ASCII based messages at a whopping baud rate of 10.

Android Audio-serial Connection

February 1, 2010 by Mike Szczys 15 Comments

This seems like something of a throwback hack. [WilinNeofoxx] has built an audio modem interface for use with his Android phone. A program running on the Android device takes the accelerometer data and converts it into a 9600bps audio signal, kind of like a dial-up modem. His custom circuit board takes that sound in through the headphone jack and demodulates it for use on the serial port of a PC. This connection to controls a flight simulator using the G1‘s motion sensors. In the video at the bottom of his post he unplugs the audio cable for a few seconds and you can hear the audio datastream coming from the phone. It’s pretty annoying so you might want to turn down those speakers before viewing it.

1964 300baud Modem Surfs The Web

May 27, 2009 by Eliot 105 Comments

[youtube=http://www.youtube.com/watch?v=X9dpXHnJXaE]

[phreakmonkey] got his hands on a great piece of old tech. It’s a 1964 Livermore Data Systems Model A Acoustic Coupler Modem. He recieved it in 1989 and recently decided to see if it would actually work. It took some digging to find a proper D25 adapter and even then the original serial adapter wasn’t working because the oscillator depends on the serial voltage. He dials in and connects at 300baud. Then logs into a remote system and fires up lynx to load Wikipedia. Lucky for [phreakmonkey] they managed to decide on a modulation standard in 1962. It’s still amazing to see this machine working 45 years later. He’d love to hear from you if you’ve used a similar device.

[via Waxy]